In an R11 version of the Third Generation Partnership Project (3GPP) Wide-band Code Division Multiple Access (WCDMA) system, multiple cells are allowed to send High Speed Downlink Packet Access (HSDPA) data to a User Equipment (UE) simultaneously. That is, the UE implements a Multi-Flow Transmission (MF-Tx) mode to enhance throughput of UEs at the cell edge and downlink throughput performance of the cell.
High Speed Packet Access (HSPA) supports the MF-Tx mode in the R11, that is, the UE at the cell edge can receive High Speed Downlink Shared Channel (HS-DSCH) from multiple cells. Correspondingly, the UE needs to feed back ACK, NACK, and PCI/CQI to each cell. On the 68th session of RANI, a consensus is reached that a UE uses a joint feedback manner to perform HS-DPCCH feedback. That is, the UE uses a single HS-DPCCH to feed back ACK (Acknowledgment), NACK, and a Channel Quality Indicator (CQI) to each cell.
In a Multi-carrier High Speed Downlink Packet Access (MC-HSDPA) mode (including Dual Carrier (DC), 4C (4 carriers), and 8C (8 carriers)), all cells belong to one NodeB and have the same coverage; when Multi Carrier (MC) is configured for the UE, all cells have basically the same uplink path loss, and therefore, demodulation requirements are met only if all cells of the base station have the same uplink HS-DPCCH power configuration.
In the MF-Tx mode, however, the UE may set up links to multiple NodeBs (NB), and each NodeB has different coverage. In the MF-Tx configuration of the UE, the uplink path loss may differ sharply between the cells (the difference may be up to 6 dB). When the same HS-DPCCH power is configured for all cells, the HS-DPCCH power arriving at the NodeB of a greater uplink path loss is low, which affects decoding performance of the HS-DPCCH on the NodeB and further affects downlink scheduling of the NodeB.